Dynamic sensitivity analysis of a mathematical model describing the effect of the macroalgaeAsparagopsis taxiformison rumen fermentation and methane production underin vitrocontinuous conditions

Author:

Blondiaux PaulORCID,Kiessé Tristan SengaORCID,Eugène MaguyORCID,Muñoz-Tamayo RafaelORCID

Abstract

AbstractRuminants plays an important role in global warming by emitting enteric methane (CH4) through the degradation of feeds by the rumen microbiota. To better understand the dynamics fermentation outputs, including methane and volatile fatty acids (VFA) production, mathematical models have been developed. Sensitivity analysis (SA) methods quantify the contribution of model input parameters (IP) to the variation of an output variable of interest. In animal science, SA are usually conducted in static condition. In this work, we hypothesized that including the dynamic aspect of the rumen fermentation to SA can be useful to inform on optimal experimental conditions aimed at quantifying the key mechanisms driving CH4and VFA production. Accordingly, the objective of this work was to conduct a dynamic SA of a rumen fermentation model underin vitrocontinuous conditions (close to the realin vivoconditions). Our model case study integrates the effect of the macroalgaeAsparagopsis taxiformis(AT) on the fermentation. AT has been identified as a potent CH4inhibitor via the presence of bromoform, an anti-methanogenic compound. We implemented two SA methods. We computed Shapley effects and full and independent Sobol indices over time for quantifying the contribution of 16 IPs to CH4(mol/h) and VFA (mol/l) variation. Our approach allows to discriminate the 3 contribution types of an IP to output variable variation (individual, via the interactions and via the dependence/correlation). We studied three diet scenarios accounting for several doses of AT relative to Dry Matter (DM): control (0% DM of AT), low treatment (LT: 0.25% DM of AT) and high treatment (HT: 0.50% DM of AT). Shapley effects revealed that hydrogen (H2) utilizers microbial group via its Monod H2affinity constant highly contributed (> 50%) to CH4variation with a constant dynamic over time for control and LT. A shift on the impact of microbial pathways driving CH4variation was revealed for HT. IPs associated with the kinetic of bromoform utilization and with the factor modeling the direct effect of bromoform on methanogenesis were identified as influential on CH4variation in the middle of fermentation. Whereas, VFA variation for the 3 diet scenarios was mainly explained by the kinetic of fibers degradation, showing a high constant contribution (> 30%) over time. In addition, the Sobol indices indicated that interactions between IPs played a role on CH4variation, which was not the case of VFA variation. However, these results are dependent on the way interactions are represented in the model. The simulations computed for the SA were also used to analyze prediction uncertainty. It was related to the dynamic of dry matter intake (DMI, g/h), increasing during the high intake activity periods and decreasing when the intake activity was low. Moreover, CH4(mol/h) simulations showed a larger variability than VFA simulations, suggesting that the reduction of the uncertainty of IPs describing the activity of the H2utilizers microbial group is a promising lead to reduce the overall model uncertainty. Our results highlighted the dynamic nature of the influence of metabolic pathways on CH4productions under an anti-methanogenic treatment. SA tools can be further exploited to design optimal experiments studying rumen fermentation and CH4mitigation strategies. These optimal experiments would be useful to build robust models that can guide the development of sustainable nutrition strategies.

Publisher

Cold Spring Harbor Laboratory

同舟云学术

1.学者识别学者识别

2.学术分析学术分析

3.人才评估人才评估

"同舟云学术"是以全球学者为主线,采集、加工和组织学术论文而形成的新型学术文献查询和分析系统,可以对全球学者进行文献检索和人才价值评估。用户可以通过关注某些学科领域的顶尖人物而持续追踪该领域的学科进展和研究前沿。经过近期的数据扩容,当前同舟云学术共收录了国内外主流学术期刊6万余种,收集的期刊论文及会议论文总量共计约1.5亿篇,并以每天添加12000余篇中外论文的速度递增。我们也可以为用户提供个性化、定制化的学者数据。欢迎来电咨询!咨询电话:010-8811{复制后删除}0370

www.globalauthorid.com

TOP

Copyright © 2019-2024 北京同舟云网络信息技术有限公司
京公网安备11010802033243号  京ICP备18003416号-3